Back-pressure check valve



n J. L. CAMERON ETAL VBACK PRESSUE CHECK VALVE Aug. 24, 194s.

2 SheetsSheet 1 Filed Feb. 8, 1945 ze-1&1.

Jamai Z.

Ffwzf Mallo BY AW# 24, 1948- Jl L. CAMERON ETL 2,447,842

BACK PRESSURE CHECK VALVE Filed Feb.- 8,' 1945 2 Sheets-Sheet 2 W I TNESSES E I N V EN '1`0RS:

BY @auf m Patented Aug. 24, 1948 UNITED STATES .PATENT OFFICE 2,447,842 BACK-PRESSURE CHECK VALVE Jarrett AL. Cameron, Orangefeld, and Frank J. Malloy, Orange, Tex., assignors to Levingston Shipbuilding' Company, Orange, Tex., a corporation of Texas Application February 8, 1945, Serial No. 576,780 12 Claims. (ci. 137-152) This invention relates to back pressure check valves of a type intended more particularly for use in connection with well drill stems and the like.

The chief aim of our invention is to, provide a back pressure check valve for well drill stems, which is simple in construction and inexpensive to produce; and which can be relied upon to ausections (not shown) of a well drill stem. Lo-

tomatically close in the event of development of back pressures in the wells land so obviate what are known as drill stern blow-outs, i. e., forcible discharge of uids either in liquid or gaseous form through the stems.

In connection with a back pressure check valve having the above attributes, it is a further aim of our invention to incorporate detent means `which will temporarily hold the closure element Fig. 1 is an axial sectional view of a back prescated within the valve chamber I3 is a pivotally hung closure flap Il which is curved in cross section, and which, when in open position is substantially concentric with the valve axis and lies substantially snug against the inner face of a coupling sleeve I2 as shown in Figs. 1 and 4, and which, when in closed position as shown in Fig. 6, bears snugly against the correspondingly rounded seat I8 at the bottom end of the sub l0 within the top of the chamber I3. The pivot connection for sure Check valve for well drill stems conveniently embodying the present invention with the parts positioned in readiness for connection to the drillstem. Fig. 2 is a fragmentary view corresponding to Fig. 1 showing how the valve parts are initially positioned within the valve housing.

Fig. 3 is a view in turn like Fig. 2 showing the valve in closed position.

Fig. 4 is a cross section of thevalve taken as indicated by the angled arrows IV-IV in Fig. '1.

Fig. 5 is another cross sectional view taken as indicated by the angled arrows -V-V in Fig. 1.

Fig. 6 is a Ffragmentary axial section taken as indicated by the angled arrows VI-VI in Fig. 3.

Fig. '7 is a perspective view of the closure element of the valve.

Fig. 8 is a perspective view of a hinge member whereby the closure element is pivotally supported; and

Fig. 9 is a view partly in 'section and partly in elevation of a detent means .associated with the actuating element of the valve.

As herein illustrated, the casing or housing of the closure flap Il comprises a small plate I9 (Fig. 8) which is fitted into the side of the upper sub I0 and secured by a pair of screws 2|l (Fig. 1). At its lower end, the plate I9 is formed with a hook 2| to outwardly engage within a rectangular aperture 22 in the closure ap adjacent the edge thereof. I

The actuating member of the valve is in the form of a 'tubular piston 23 which has a ared head 424 at the top surrounded by a band 25 of rubber or the like for huid-tight tment circumferentially within thel coupling sleeve I2. diameter of the body portion of thel piston 23 is somewhat less than that of the enlarged bore portion 26 at the upper end of the sub II with resultant provision of a clearance 21 all around it when said piston is in the lowered position oi. Fig. 1*. a circumferentially notched guiding -iiange 28 that slidably engages the interior of the coupling sleeve I2, said flange being adapted torest on the annular shoulder formed by the top end of the sub II within the valve chamber. Slidably engaged within the piston 23 is a tubular detent element 30 with a st'op flange 3| at its upper end, the bore of said element being equal in diameter to that of the main bores 32 and 33 of the lsubs I0 and II and internally beveled at the top at an angle corresponding to the internal flare of the head 24 of said piston. As shown, the sub II is likewise beveled internally of the top of its bore by a split spring band 39, said band 39 being held in place by a nut collar 40 threadedly engaged on The Medially of its height, the piston 23 has,

3 the protruding bottom end of the element 30 and secured against accidental displacement by a set screw 4|. For reasons also hereinafter explained the piston 23 is provided immediately below its flared head 24, with downwardly and outwardly inclined apertures 42, and the spring band 39 with circumferentially arranged perforations 43 and 44 respectively adjacent its upper and lower edges.

In assembling the valve, the spring band 39 is compressed and the detent element 30 inserted into the tubular piston 23 as shown in Fig. 2 with its upper end projecting, whereupon the nut collar 4D is applied and secured by the set screw 4I. With this accomplished, the piston 23 is inserted into the coupling sleeve I2Vand the bottom sub Il finally screwed into place, the movable parts being then positioned as in Fig. 2 with the edge of the flared head 24 of said piston engaging behind the closure flap I1 which is chamfered as at Ha to permit this. The assembled valve, made ready as .inst explained. is then connected to the drill stem adjacent the lower end of the latter preferably just above the drill collar.

With the closure ap l1 held open as in Fig. 2 it will be seen that the main bores of the subs I0 and Ii are entirely unobstructed so that string tools such as drills, swabs, gages or stirrers ordinarily used in normal operations inside the drill stern may be readily introduced through said stem from above without hindrance. Temporary locking of the valve in open position is advantageous incident to the drilling since it allows the weight of the mud to remain in the hole, and at the same time eliminates any air which might accumulate and which would have to be otherwise released before drilling or circulation of mud ls started. The parts will remain in the positionsin which they are shown in Fig. 2 until the mud pumps are started and the drilling is commenced. Upon passage of the drilling iluid under pressure downward through the valve, the detent element will yield to displacement and descend within the piston 23 until its stop ange rests on top of the sub Il as shown in Fig. 1`, with attendant freeing of the spring band 39 which consequently will expand and coact with said stop flange to prevent subsequent rise of said element within said piston. Thereafter throughout the drilling operation the movable parts of the valve will remain in the position of Fig. 1. However, if back pressure should for any reason develop in stem .from within the well, the piston 23 and thedetent element 30 will be bodily raised by direct action of the pressure against the bottom of the nut collar 40 and the bottom of the head 24 with the result that upon withdrawal of the tool string to a level slightly above the seat I8, the closure flap I1 will be swung inward by action of the liare on said member and will itself be subjected to the force of the pressure from below and thereby be moved to the fully closed position in which it is shown in Fig. 3. The drain apertures 42 in the member 23 allow circulation ln the event that ne sand particles should by-pass the packing ring 25 and so prevent clogging; while the perforations 43 and 44 in the split ring permit the uid used in the drilling to augment the spring eiect of the ring and thereby assist in counteracting the external pressure which would tend to collapse said ring. In this way, we insure against rising of the detent tube to its original elevated holding position after it has once been depressed.

Although our improved back pressure check valve can be interposed at any desired point in the drill stem. we preferably place it, as previously stated, near the bottom of the stem just behind the drill collar (not shown) of the bit. In practice its external dimensions are made equal to that oi! the tool Joint and its internal dimensions-slightly larger than those of the drill stem proper.

Having thus described our invention, we claim:

1. A check valve for a connection axially of a hollow well drill stem or the like including a tubular valve casing; a closure element adapted to cooperate with a valve seat withinvthe casing; detent means for initially holding the closure element away from its seat but capable of responding to a predetermined velocity of fluid through the valve casing from above to release the closure element; and actuating means capable of responding subsequently to a predetermined velocity ot fluid in the opposite direction to move the closure element into engagement with its seat.

2. A check valve according to claim 1, in which there is a diametricallyenlarged chamber medially of the valve. casing; in which the closure element is in the form of a pivotally-suspended flap curved and normally positioned at one side of the chamber substantially in concentric relation to the chamber wall: and in which the seat against which said flap closes is correspondingly curved.

3. A check valve for connection axially of a hollow well drill stem or the like including a tubular valve casing providing a diametrically enlarged chamber; a pivotally-suspended closure ap adapted to cooperate with a valve seat at the top of the chamber and normally in open position; and a tubular actuating piston adjacent the vbottom of the chamber having a projection at the top reaching behind the valve flap, said piston being responsive to upward displacement by a predetermined velocity of iiuid in the valve casing from below to move the closure ilap into engagement with its seat.

4. A back pressure check valve according to claim 3, in which the piston has a head ilange surrounded by a band of resilient material for uid-tlght tment within the chamber.

5. A back pressure check valve according to claim 3. in which the valve casing comprises a pair of axially aligned subs in spaced relation and respectively provided with coupling means, and a tubular coupling sleeve connecting the contiguous ends of the two subs.

6. A back pressure check valve according to .claim 3, further including a detent element in the form of a tube within the piston, and associated means for initially holding the tube projected above the piston in the path of the closure flap to prevent closing of the latter, said detent element being displaceable downwardly by a predetermined velocity of fluid in the valve casing from above so as to release said ap in readiness foractuation by the piston.

7. A back pressure check valve according to claim 3, further including a detent element in the form of a tube within the piston, and associated means for initially holding the tube projected above the piston in the path of the closure ilap to prevent closing of the latter, said detent ele- 8. A check valve for connection axially of a hollow well drill stem or the like including a tubular valve casing providing a diametrically-enlarged chamber; a closure flap pivotally suspended in Y the chamber at one side and adapted to cooperate with a valve seat at the top .of the chamber; a

tubular actuating piston adjacent the bottom of the chamber having. a head flange which reaches behind the closure iiap, said piston being responsive to upward displacement by a predetermined velocity of fluid in the valve casing from below to move the flap into engagement with its seat; and a tubular detent slidably engaged in the piston for initially holding the flap in open posi-- tion, and responsive to downward displacement by a predetermined velocity of fluid in the valve casing from above and having a stop shoulder at the top; and a split spring band lodged in a circumferential recess at the lower end of the detent for frictionally engaging the bore of the piston to hold the tube up in the-path of the flap i and adapted, upon depression of the tube, to expandY and coact with the aforesaid stop shoulder in locking the tube to the piston.

9. A back pressure check valve according to claim 8, in which the head flange of the piston is surrounded by a band of resilient material `for fluid-tight fitment Within the valve chamber; and in which the detenthas a jacket of similar material above the split band for fluid-tight fitment within the piston when in its lowered position.

10. A back pressure check valve according to claim 8, in which the head flange of the piston is surrounded by a band oiv resilient material for duid-tight fitment within the valve chamber: in

' Number which said pistonl is provided immediately below its head flange with a circumferential series of downwardly and outwardly inclined apertures; and in which the' detent has a jacket o! resilient material above the split spring band for fluid.-

tight fitment within the piston when in its low-` ered position.

11. A back pressure check valve according-to claim 8, in which the split spring band is provided with a circumferential series of holes which permit entry of :Huid to its interior after it has been expanded.

12. A back pressure check valve according to claim 8, in which the head flange of the piston is surrounded by a band of resilient material for fluid-tight fitment within the valve chamber; in which said piston is provided immediately below its head flange with a circumferential series oi downwardly and outwardly inclined apertures; in which the detent has a'jacket of resilient material above the split spring band for duid-tight fitment within-the piston when in its lowered position; and in which the split spring band is provided with a circumferential series of holes for passage of uid to its interior after it has been expanded.

JARRETT L. CAMERON.

FRANK J. MALLOY.

REFERENCES CITED lThe following references are of record in the ille of this patent:

UNITED STATES PATENTS Name Date 2,256,119 Lillich Sept. 16, 1941 2,354,310 Goodwin July 25. 1944 

